From 879ab76ff9ff261cab9aad9dcce4dd6d72b0e204 Mon Sep 17 00:00:00 2001
From: Alexey Zholtikov <git@zh.com.ru>
Date: Sun, 14 Sep 2025 08:05:40 +0300
Subject: [PATCH] wip:

---
 include/zh_avr_ac_dimmer.h |  2 ++
 zh_avr_ac_dimmer.c         | 41 +++++++++++++++++++-------------------
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/include/zh_avr_ac_dimmer.h b/include/zh_avr_ac_dimmer.h
index 0c97db5..d87c85c 100644
--- a/include/zh_avr_ac_dimmer.h
+++ b/include/zh_avr_ac_dimmer.h
@@ -7,6 +7,8 @@
 #include "avr/interrupt.h"
 #include "util/delay.h"
 
+#define ZH_TRIAC_TIME 2 // Triac turn-on time (in microseconds). Depends on the type of triac. Tested on BTA16-600.
+
 #define ZH_AVR_AC_DIMMER_INIT_CONFIG_DEFAULT() \
     {                                          \
         .ac_dimmer_frequency = ZH_50HZ,        \
diff --git a/zh_avr_ac_dimmer.c b/zh_avr_ac_dimmer.c
index 32ec883..0256eef 100644
--- a/zh_avr_ac_dimmer.c
+++ b/zh_avr_ac_dimmer.c
@@ -5,7 +5,6 @@ volatile static bool _is_dimmer_work = false;
 volatile static uint8_t _dimmer_value = 0;
 volatile static uint8_t _dimmer_count = 0;
 static bool _is_initialized = false;
-static uint8_t _prescaler = 0;
 
 static avr_err_t _zh_avr_ac_dimmer_validate_config(const zh_avr_ac_dimmer_init_config_t *config);
 static void _zh_avr_ac_dimmer_gpio_init(void);
@@ -77,22 +76,23 @@ void zh_avr_ac_dimmer_isr_handler(void)
     {
         if (_dimmer_value != 0)
         {
-            if (_dimmer_value == 100)
+            if (_dimmer_value >= 100)
             {
+                TIMSK0 &= ~(1 << OCIE0A);
                 switch (_init_config.triac_port)
                 {
                 case AVR_PORTB:
                     PORTB |= (1 << _init_config.triac_gpio);
-                    _delay_us(2);
+                    _delay_us(ZH_TRIAC_TIME);
                     PORTB &= ~(1 << _init_config.triac_gpio);
                     break;
                 case AVR_PORTC:
                     PORTC |= (1 << _init_config.triac_gpio);
-                    _delay_us(2);
+                    _delay_us(ZH_TRIAC_TIME);
                     PORTC &= ~(1 << _init_config.triac_gpio);
                 case AVR_PORTD:
                     PORTD |= (1 << _init_config.triac_gpio);
-                    _delay_us(2);
+                    _delay_us(ZH_TRIAC_TIME);
                     PORTD &= ~(1 << _init_config.triac_gpio);
                     break;
                 default:
@@ -102,7 +102,7 @@ void zh_avr_ac_dimmer_isr_handler(void)
             else
             {
                 TCNT0 = 0;
-                TCCR0B |= _prescaler;
+                TIFR0 = (1 << OCF0A);
                 TIMSK0 |= (1 << OCIE0A);
             }
         }
@@ -174,15 +174,15 @@ static avr_err_t _zh_avr_ac_dimmer_timer_init(void)
         {
         case ZH_50HZ:
             OCR0A = 99;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         case ZH_60HZ:
             OCR0A = 82;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         case ZH_400HZ:
             OCR0A = 99;
-            _prescaler = (1 << CS00);
+            TCCR0B |= (1 << CS00);
             break;
         default:
             break;
@@ -193,15 +193,15 @@ static avr_err_t _zh_avr_ac_dimmer_timer_init(void)
         {
         case ZH_50HZ:
             OCR0A = 24;
-            _prescaler = (1 << CS01) | (1 << CS00);
+            TCCR0B |= (1 << CS01) | (1 << CS00);
             break;
         case ZH_60HZ:
             OCR0A = 165;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         case ZH_400HZ:
             OCR0A = 24;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         default:
             break;
@@ -212,15 +212,15 @@ static avr_err_t _zh_avr_ac_dimmer_timer_init(void)
         {
         case ZH_50HZ:
             OCR0A = 249;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         case ZH_60HZ:
             OCR0A = 207;
-            _prescaler = (1 << CS01);
+            TCCR0B |= (1 << CS01);
             break;
         case ZH_400HZ:
             OCR0A = 249;
-            _prescaler = (1 << CS00);
+            TCCR0B |= (1 << CS00);
             break;
         default:
             break;
@@ -235,25 +235,24 @@ static avr_err_t _zh_avr_ac_dimmer_timer_init(void)
 
 ISR(TIMER0_COMPA_vect)
 {
-    if (_dimmer_count == (100 - _dimmer_value))
+    if (_dimmer_count >= (100 - _dimmer_value))
     {
         _dimmer_count = 0;
-        TCCR0B = 0;
-        TIMSK0 = 0;
+        TIMSK0 &= ~(1 << OCIE0A);
         switch (_init_config.triac_port)
         {
         case AVR_PORTB:
             PORTB |= (1 << _init_config.triac_gpio);
-            _delay_us(2);
+            _delay_us(ZH_TRIAC_TIME);
             PORTB &= ~(1 << _init_config.triac_gpio);
             break;
         case AVR_PORTC:
             PORTC |= (1 << _init_config.triac_gpio);
-            _delay_us(2);
+            _delay_us(ZH_TRIAC_TIME);
             PORTC &= ~(1 << _init_config.triac_gpio);
         case AVR_PORTD:
             PORTD |= (1 << _init_config.triac_gpio);
-            _delay_us(2);
+            _delay_us(ZH_TRIAC_TIME);
             PORTD &= ~(1 << _init_config.triac_gpio);
             break;
         default: